I need help! second miscarriage at 23yrs old

So my first miscarriage was on the 13th October and I've literally gone straight into another pregnancy but started bleeding heavy today 29th November. Both babies were about 5 weeks. Is there anyone else out there roughly the same age who's had the same problem? Is there something wrong with me or is it because I didn't wait for a cycle before trying again. Unfortunately I can't get any answers from the doctors as they don't test until you've had three miscarriages and I don't think I'll be able to get through another one. Really feeling low.